Testing the parity of the Higgs boson through linearly polarized gluons

The role of transverse momentum dependent (TMD) gluonic parton distributions is discussed for proton collisions at high energies. In particular the production of two real photons in proton collisions in the kinematical regime of small transverse pair momenta may be used to obtain information on gluon TMDs. While spin-dependent gluon TMDs can be studied in polarized proton collisions at RHIC the effect of linearly polarized gluons on unpolarized proton collisions at the LHC may be utilized to determine the parity of the Higgs boson.